I'm not sure if it's an option in the settings now or not but if you go to `about:config` in firefox and search for `browser.warnOnQuit` you can make sure that'

I'm not sure if it's an option in the settings now or not but if you go to `about:config` in firefox and search for `browser.warnOnQuit` you can make sure that's set to `true`. Another favorite of mine: `browser.tabs.closeWindowWithLastTab` set to `false`. This lets me cmd-w as many times as i want but it won't close the window I have open.